Who is The Okonkwo Siblings from No Longer at Ease and what is their importance?

Esther Okonkwo, the firstborn, becomes a teacher when Obi is very young, and everyone is told to call her Miss out of respect, but Obi sometimes slips up. Esther is the mother of three, and upon her mother's death is expected to look after her father. Janet, the second oldest, is the mother of two. Agnes, the third oldest, is the mother of one, having lost a little girl while still practically a child herself. After the evening's prayer service, Hannah asks her to carry the sleeping grandchildren to bed, but to make sure they urinate first. Agnes grabs the first by the wrist and pulls, earning a rebuke, to which Obi adds: it can cause a child's soul to leave the body and not find its way back. Mother smiles without amusement. Charity, the fourth oldest and Obi's immediate elder, is the only sister with whom Obi quarrels. He makes fun of her Ibo name, turning it from "a girl is also good" (expressing her father Isaac's resignation at getting a fourth daughter) into "A girl is not good". For this, Obi receives beatings once their mother is not looking. Charity is as strong as any boy and feared in the neighborhood. Obi's younger brother, John, is still in school, and Obi agrees to pay his fees to relieve the parents' burden. The youngest sibling, Eunice, is still at home with distant relatives Joy and Mercy, who have been sent to learn housekeeping from Mrs. Okonkwo. Umuofians remark about all of the children moving away to seek their fortunes.